Reinforced hose of relatively hard yet flexible materials, such as nylon, have come into use for installation in air conditioning equipment for conducting refrigerant fluids, automotive hydraulic brake systems, and other application in which they are subject to high pressures and/or corrosive fluids. In air conditioning applications, for example, pressures may be as high as 500 p.s.i. while in hydraulic system applications the pressures may reach 3,000 p.s.i.
Hose of these materials is very difficult to stretch over barbs of conventional hose coupling nipples in which the barbs are of larger diameter than the inside diameter of the hose and is easily damaged when an effort is made to accomplish this. Moreover, when installed on such couplings in which the barbs are of increasing diameter from the outer end of the nipple toward the inner end, the joint has a tendency to loosen and leak when subjected to internal fluid pressure and/or mechanical pullout forces.